Specialised cells, tissues, organs and systemsIB MYP Sciences: Subtopic test

1. 1
   A doctor in Riyadh explains to a class how the human body is organised, using the stomach as an example. The stomach wall contains muscle tissue that churns food, glandular tissue that makes digestive juices, and a lining of protective cells. The stomach is part of the digestive system.

   (a)

   Which list shows the levels of organisation in the body from smallest to largest?

   [1 mark]

   • AOrgan, tissue, cell, organ system
   • BTissue, cell, organ, organ system
   • CCell, organ, tissue, organ system
   • DCell, tissue, organ, organ system

   (b)

   At which level of organisation is the stomach?

   [1 mark]

   • AAn organ
   • BA tissue
   • CAn organ system
   • DA specialised cell

   (c)

   Explain why the stomach is called an organ rather than a tissue.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A student is comparing specialised cells in humans and plants, including red blood cells, sperm cells and the root hair cells of a seedling.

   (a)

   Which feature helps a root hair cell to absorb water from the soil?

   [1 mark]

   • AMany chloroplasts to absorb light
   • BA long, thin extension that gives a large surface area
   • CA tail for swimming
   • DLots of haemoglobin to carry oxygen

   (b)

   Which specialised cell has a tail and many mitochondria?

   [1 mark]

   • ANerve cell
   • BRed blood cell
   • CSperm cell
   • DPalisade cell

   (c)

   Explain how the structure of a red blood cell makes it suited to carrying oxygen.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   Biologists in Brazil study the structure of a leaf. The leaf has a protective layer of cells on its surface, palisade cells just below the upper surface where most photosynthesis takes place, and veins that carry water and sugars through the leaf.

   (a)

   Describe how a palisade cell is adapted for photosynthesis.

   [3 marks]

   (b)

   Using the leaf as your example, explain what is meant by a tissue and by an organ.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A company in Dubai plans an indoor vertical farm in which lettuce plants grow in stacked trays under LED lights, with no soil. The company's scientists want to know how lettuce plants respond to different amounts of light, and the company is also deciding whether to build the farm.

   (a)

   Plan an investigation to test a hypothesis about how the amount of light affects the growth of lettuce plants. In your answer, state a hypothesis with a scientific reason that refers to palisade cells, identify the variables, and describe a safe method.

   [6 marks]

   (b)

   Discuss and evaluate the company's plan to build an indoor vertical farm. Consider social, economic and environmental implications, and finish with a justified conclusion.

   [6 marks]

   Total for question 4: 12 marks

End of questions